The Administrative Core will provide leadership for this U19 Cooperative Agreement on the immune response to orthopoxviruses. It will integrate and enhance the scientific activities of principal investigators at Washington University School of Medicine in St. Louis and at Oregon Heath and Sciences University in Portland. The Specific Aims of the Administrative Core are to: 1. Coordinate and integrate U19 activities to expedite generation of outstanding research findings; 2. Facilitate interaction among principal investigators with particular emphasis on programs to enhance sharing of preliminary data and reagents for collaboration; 3. Evaluate progress of U19 scientific work and prioritize as needed; 4. Identify new research opportunities; and 5. Work with NIAID program officials to facilitate interactions with other U19's supported by RFA-AI-12- 048. Thus the Administrative Core will endeavor to expedite the generation of new research findings.